Control mechanism for selective engagement and disengagement of a motor drive

ABSTRACT

A control mechanism for the selective engagement and disengagement of a motor drive includes an elongated handle which is connected to the control arm of the motor drive wherein the position of the control arm determines whether the motor drive is engaged or disengaged. The handle is selectively movable to two positions corresponding to the engaging and disengaging positions of the control arm. The handle is resiliently urged to its positions. Locking structure is provided to selectively hold the handle in each of the positions.

BACKGROUND OF INVENTION

This invention relates to a control mechanism for the selectiveengagement and disengagement of a motor drive. Frequently motor drivessuch as gear boxes are provided with control handles which are pivotedto one of two positions. In one of the positions the motor drive isengaged and in the other position the motor drive is disengaged. Variousforms of such motor drives have been used wherein the control arms areinconveniently located. For example, tow trucks include a pair of motordrives located generally along the longitudinal center of the truckremote from the rear end of the truck. It is difficult for an operatorto reach the control arm because of its location away from the sideedges of the truck. Accordingly, it would be desirable if some mechanismcould be provided which would permit the operator to readily move thecontrol arm to its engaging and disengaging positions while remaining ata convenient location at the side of the truck.

SUMMARY OF INVENTION

An object of this invention is to provide a control mechanism whichfulfills the above needs.

A further object of this invention is to provide such a controlmechanism which is particularly useful for controlling the engagementand disengagement of a winch having a cable.

A further object of this invention is to provide such a controlmechanism which is particularly usable on tow trucks wherein two sets ofmechanisms would be provided.

In accordance with this invention the control mechanism includes anelongated handle which would be connected to the control arm of themotor drive so that by moving the handle to one of two positions thecontrol arm is correspondingly moved to either its engaging ordisengaging position. The handle is resiliently urged to its positions.Lock means is provided for selectively holding the handle in each of thetwo positions.

The lock means may include a bracket having an upstanding projectionwith a slot through which the handle slides. A second projection orabutment member would be mounted spaced from the first projection orabutment member and would also contain a hole for permitting the handleto slide through that abutment member. The handle would be rotatablyconnected to the control arm and the handle would include a stop membersuch as a pin. By rotating the handle, the handle could be moved forselectively passing the pin through the slot so that the pin canselectively abut against the projections.

THE DRAWINGS

FIG. 1 is a side elevation view of a conventional tow truckincorporating the control mechanism of this invention;

FIG. 2 is an elevation view taken along the line 2--2 of FIG. 1;

FIG. 3 is a top plan view of the mechanism shown in FIG. 2;

FIG. 4 is an end elevation view taken from the right hand side of FIG.3;

FIG. 5 is an elevation view showing the mechanism in its positionwherein the motor drive is disengaged; and

FIG. 6 is a perspective view of the mechanism shown in FIGS. 1-5.

DETAILED DESCRIPTION

FIG. 1 illustrates a conventional tow truck 1 with which the mechanism10 which is the subject of this invention may be used. Tow truck 1 wouldinclude, for example, a pair of motor driven winches 2 each having acable 3 which extends over boom 4. A lifting cylinder 5 is mounted toboom 4 and frame assembly 6. Lifting cylinder 5 is pivotally mounted toselectively permit the boom to be elevated for a towing operation. Ahook 7 is provided at the end of each cable 3. As shown in FIG. 1 hook 7is secured in a retaining strap 8 when the truck 10 is not being usedfor towing purposes.

When it is desired to use truck 1 for towing, for example, a vehicle, itis necessary to extend cables 3. This should be done by disengaging themotor drive gear box so that the cables 3 can become free wheeling andthus can be readily pulled away from boom 4 to the necessary length forattachment to the vehicle. After the hooks 7 have been attached to thevehicle it is necessary to reengage the motor drive so that the winch 2can be rotated in the reverse direction to pull the vehicle toward thetruck 1 whereupon boom 4 is elevated and the truck can be towed.

As shown in FIG. 3 the mechanism for operating winch 2 includes ahydraulically operated motor 9 connected to gear box 11 to drive thewinch 2 for winding cable 3. The engagement or disengagement of themotor drive is controlled by arm or lever 12. For example, in theposition shown in FIG. 2 control arms 12 are in the engaged positionwherein cable 3 is not free wheeling. In the position shown in FIG. 5,however, arm 12 has been pivoted to, for example, a generally verticalposition, wherein the motor drive is disengaged.

The above description relates to generally conventional structure on thetow trucks. With such conventional tow trucks arms 12 are generallyalong the longitudinal center of the tow truck body remote from the rearend or hooks 7 of truck 1. Additionally, because arms 12 are locatedgenerally along the longitudinal center of the tow truck body, the armsare relatively inaccessible to the operator who would be standing on theground adjacent the truck body. Various techniques have been used tocontrol the engagement or disengagement of the motor drive. For example,an operator might climb on the truck body, pull the arm 12 to pivot itto its desired position and then insert some locking structure adjacentthe arm to hold or wedge it in a fixed position. When it is desired toagain move the arm to its original position the operator must againcrawl on the truck and remove the locking structure. Since tow trucksconventionally include two sets of such motor drives it is necessary torepeat this procedure from each side of the truck.

Control mechanism 10 overcomes the inconveniences which accompany theconventional manners of controlling the selective engagement anddisengagement of the motor drive. As shown herein mechanism 10 includesan elongated handle 14 connected at one end to arm 12. Any suitablemanner of connection may be used. In the preferred practice of theinvention the connection is one which permits handle 12 to be rotated atleast 90° by the rotatable connection 16. This could be done by passinghandle 14 through an eye and providing a pin or abutments on handle 14to prevent the handle from being removed from the eye.

Mechanism 10 also includes a pair of abutment members for selectivelylocking handle 14 in two different positions. In the preferred practiceof the invention the abutment members comprise a bracket 18 having abase 20 with a downward extension 22 mounted to an L-shaped bracket 24secured to frame 6. Post 25 provides added support for base 20. Base 20also includes an upward extension 26 having an elongated verticallyextending slot 28 through which handle 14 passes. An eye 29 is connectedto base 20. Eye 29 has a ring formation 30, with handle 14 passingthrough the hole or opening 32 in the eye. Eye 29 functions as a secondprojection or abutment member.

A stop member preferably in the form of a shear pin 34 is fixedlysecured to handle 14 and is dimensioned so that when handle 14 is in theposition shown in solid in FIG. 6 pin 34 will press against abutment 26to prevent handle 14 from moving toward the left hand side of FIG. 6.When however, handle 14 is rotated to the position shown in phantom, the90° rotation permits pin 34 to be aligned with slot 28 and thus passthrough slot 28 until it engages ring 30 of eye 29. Further movementtoward the left is prevented by pin 34 contacting ring 30.

A spring 36 is mounted around handle 14 by being secured between disks38, 40. Disk 38 is secured to handle 14 and disk 40 is secured to eye29. Spring 36 acts to resiliently urge handle 14 in the direction towardthe left in FIG. 6. Accordingly, when pin 34 abuts against flange orprojection 26 or when pin 34 abuts against ring 30 the handle is lockedin that respective position because of the resilient urging by spring 36of the stop member or pin 34 against its corresponding abutment member26 or 28.

As shown in FIG. 6 base 20 of bracket 18 is disposed at anonperpendicular and nonparallel angle to handle 14. Similarly, flangeor offset 26 is also disposed at a nonperpendicular and nonparallelangle to both base 20 and handle 14. Handle 14 includes a grippingmember 42 located on an offset extension 44 for convenient manipulationof handle 14.

As illustrated, when mechanism 10 is used on a tow truck two sets ofidentical structure would be provided, one for each arm 12.

In operation when it is desired to tow a vehicle, truck 1 would bedriven to a location near the vehicle. During this stage of operationmechanism 10 would be in the condition shown in FIG. 2 and shown inphantom in FIG. 6 wherein arm 12 is disposed in its motor drive engagedposition. While in this position, cables 3 are not freewheeling. When itis desired to secure the hooks 7 to the vehicle to be towed, handles 14are pulled away from the center of the truck body (i.e. toward the rightin FIG. 6) in opposition to the resilient force of spring 36. Thispulling action continues until pin 34 passes through slot 28. Ifnecessary, handle 14 may be rotated to align pin 34 with slot 28. Afterpin 34 has passed through slot 28 handle 14 is rotated so that pin 34 isout of alignment with slot 28 and pin 34 abuts against flange 26.Because of the resilient force of spring 36 handle 14 is being urgedtoward the left of FIG. 6 and is locked in position by the contact ofpin 34 against the outer surface of flange 26. This motion causescontrol arm 12 to be moved from the position shown in FIG. 2 to itssecond or disengaged position of FIG. 5. With the motor drive disengagedcables 3 becomes freewheeling. Hook 7 is removed from retaining strap 8and the hook is pulled the necessary length for being secured to thevehicle to be towed. Handle 14 is then rotated by again grasping gripmember 42 so that pin 34 is again aligned with slot 28. If necessaryhandle 14 might be pulled slightly to the right of FIG. 6 so that pin 34is not in sliding contact with the surface of flange or plate 26. Afterpin 34 is aligned with slot 28 the resilient force of spring 36 urgeshandle 14 to the left and this motion continues until pin 34 contactsthe loop 30 of abutment member 28 to again lock handle 14 in its secondposition. When in this second position arm 12 has been moved to itsmotor drive engagement position shown in FIG. 2. This procedure isrepeated for the other drive. Upon actuation of the hydraulic motor,each cable 3 is retracted or rewound on its spool or gear box 11 to pullthe vehicle closer to tow truck 1 for the conventional towing operation.

It is to be understood that while this invention has particular utilityand has been described with respect to the selective engagement anddisengagement of a motor drive on a tow truck, the concepts of thisinvention may be practiced in any condition where it is desired toactuate a remotely located arm.

What is claimed is:
 1. A control mechanism for selective engagement anddisengagement of a motor drive having a control arm which is pivotallymovable in a plane to a first engaging position and a second disengagingposition, said mechanism comprising an elongated handle, said handlehaving a free end which may be grasped by a user, said handle having anopposite end pivotally and rotatably connected to the pivotally movablecontrol arm, said handle being selectively slidably movably mounted in alongitudinal direction in the plan of control arm movement to a firstposition and a second position corresponding to the engaging anddisengaging positions of the pivotally movable control arm, lock meansfor selectively holding said handle in each of said two positions, saidlock means comprising a pair of longitudinally spaced abutments, saidhandle being rotatably mounted for selective contact with each of saidabutments in accordance with the sliding and rotatable movements of saidhandle, and resilient means for selectively maintaining said handle in alocked position.
 2. In a tow truck having a motor drive which drives awinch having a towing cable thereon, said motor drive having a controlarm for controlling selective engagement and disengagement of said motordrive, and said control arm being pivotally mounted for pivotal movementin a plane to a first engaging position and to a second disengagingposition, the improvement being in a control mechanism for the selectiveengagement and disengagement of said motor drive, said mechanismincluding a elongated handle, said handle having a free end extending toa side of said truck whereby said free end may be grasped by a userstanding at the side of said truck said handle having an opposite endpivotally and rotatably connected to said control arm, said handle beingselectively slidably movably mounted in a longitudinal direction in saidplane of control arm movement to a first position and a second positioncorresponding to the engaging and disengaging positions of said controlarm, lock means for selectively holding said handle in each of said twopositions, said lock means comprising a pair of longitudinally spacedabutments, said handle being rotatably mounted for selective contactwith each of said abutments in accordance with the sliding and rotatablemovements of said handle, and resilient means for selectivelymaintaining said handle in its locked position.
 3. In the truck of claim2 wherein each of said abutments has an opening, said handle beingslidably mounted for said movement through said openings in saidabutments, and a stop member secured to said handle for selectivecontact with each of said abutments.
 4. In the truck of claim 3 whereinone of said abutments comprises a plate having a longitudinal slot, saidslot comprising said opening for the movement of said handle, and saidstop member being a pin whereby rotation of said handle permits said pinto be moved into and out of alignment with said slot.
 5. In the truck ofclaim 4 wherein the other of said abutments comprises an eye, and saidplate being located between said free end and said eye.
 6. In the truckof claim 5 wherein said plate is mounted at a nonperpendicular andnonparallel angle to said handle.
 7. In the truck of claim 6 including abracket for securement to a support member, said plate comprising anoffset extension of said bracket, and said eye being mounted to saidbracket.
 8. The truck of claim 2 including two sets of said control armsaligned with each other for pivotal movement in said plane, and aseparate one of said mechanisms being connected to each of said controlarms.
 9. A control mechanism for selective engagement and disengagementof a motor drive having a control arm which is movable to a firstengaging position and a second disengaging position, said mechanismcomprising an elongated handle for connection to the control arm, saidhandle being selectively movably mounted to a first position and asecond position corresponding to the engaging and disengaging positionsof the control arm, lock means for selectively holding said handle ineach of said two positions, resilient means for selectively maintainingsaid handle in its locked position, said lock means including two spacedabutments, each of said abutments having an opening, said handle beingslidably mounted for said movement through said openings in saidabutments, a stop member secured to said handle for selective contactwith each of said abutments, one of said abutments comprising a platehaving a longitudinal slot, said slot comprising said opening for themovement of said handle, said stop member being a pin, said handle beingrotatable to permit said pin to be moved into and out of alignment withsaid slot, the other of said abutments comprising an eye, said handlehaving a free end which may be grasped by an operator of said mechanism,said plate being located between said free end and said eye, said platebeing mounted at a nonperpendicular and nonparallel angle to saidhandle, a bracket for securement to a support member, said platecomprising an offset extension of said bracket, said eye being mountedto said bracket, said bracket including a base portion mounted at anonparallel and nonperpendicular angle to said handle and to said plate,and said eye being mounted perpendicularly to said base.
 10. Themechanism of claim 9, wherein said resilient means is a coil springfixed to said handle and mounted between a pair of disks on a side ofsaid eye remote from said plate.
 11. The mechanism of claim 10, incombination therewith, wherein there are two identical sets of saidmechanism.
 12. The mechanism of claim 11, in combination with a motordrive having a control arm to control the engagement and disengagementof said motor drive, and said handle being mounted to said control armfor controlling the position of said arm in accordance with the positionof said handle.
 13. The combination of claim 12 wherein said motor drivedrives a winch having a cable thereon.
 14. The combination of claim 12wherein said motor drive is part of a tow truck, and a hook beingsecured to said cable.
 15. The combination of claim 14 wherein saidcontrol arm is located generally along the longitudinal center of saidtruck remote from said hook, and said handle extending to an edge of aside of said truck.